The following method for soldering without the use of a soldering ironis given in the _Techniker_:

The parts to be joined are made to fit accurately, either by filingor on a lathe. The surfaces are moistened with the soldering fluid, asmooth piece of tin foil laid on, and the pieces pressed together andtightly wired. The article is then heated over the fire or by means ofa lamp until the tin foil melts. In this way two pieces of brass can besoldered together so nicely that the joint can scarcely be found.

With good soft solder, nearly all kinds of soldering can be done overa lamp without the use of a "copper." If several piaces have tobe soldered on the same piece, it is well to use solder of unlikefusibility. If the first piece is soldered with fine solder composed of2 parts of lead, 1 of tin, and 2 of bismuth, there is no danger of itsmelting when another place near it is soldered with bismuth solder, madeof 4 parts of lead, 4 of tin, and 1 of bismuth, for their melting pointsdiffer so much that the former will not melt when the latter does. Manysolders do not form any malleable compounds.

In soldering together brass, copper, or iron, hard solder must beemployed; for example, a solder made of equal parts of brass and silver(!). For iron, copper, or brass of high melting point, a good solder isobtained by rolling a silver coin out thin, for it furnishes a tenaciouscompound, and one that is not too expensive, since silver stretches outwell. Borax is the best flux for hard soldering. It dissolves the oxideswhich form on the surface of the metal, and protects it from furtheroxidation, so that the solder comes into actual contact with thesurfaces of the metal. For soft soldering, the well-known fluid, made bysaturating equal parts of water and hydrochloric acid with zinc, is tobe used. In using common solder rosin is the cheapest and best flux. Italso has this advantage, that it does not rust the article that it isused on.--_Deutsche Industrie Zeitung_.

* * * * *

WORKING COPPER ORES AT SPENCEVILLE.

From a letter in the Grass Valley _Tidings_ we make the followingextracts:

The Spenceville Copper Mining Company have 43 acres of copper-bearingground and 100 acres of adjoining land, which was bought for the timber.There are a hoisting works, mill, roasting sheds, and leaching vats onthe ground, and they cover several acres.

On going around with Mr. Ellis, the first place we came to was the mineproper, which is simply an immense opening in the ground covering aboutone half of an acre, and about 80 feet deep. It has an incline runningdown into it, by which the ore is hoisted to the surface. Standing onthe brink of this opening and looking down, we could see the men atwork, some drilling, others filling and running the cars to the inclineto be hoisted to the surface.

The ore is found in a sort of chloritic slate and iron pyrites whichfollow the ledge all around. The ore itself is a fine-grained pyrite,with a grayish color, and it is well suited by its sulphur and lowcopper contents, as well as by its properties for heap roasting. In heaproasting, the ore is hand-broken by Chinamen into small lumps beforebeing hoisted to the surface. From the landing on the surface it is runout on long tracks under sheds, dumped around a loose brick flue and ona few sticks of wood formed in the shape of a V, which runs to the fluesto give a draught. Layers of brush are put on at intervals through thepile. The smaller lumps are placed in the core of the heap, the largerlumps thrown upon them, and 40 tons of tank residues thrown over all toexclude excess of air; 500 lb. of salt is then distributed through thepile, and it is then set afire. After well alight the draught-holes areclosed up, and the pile is left to burn, which it does for six months.At the expiration of that time the pile is broken into and sorted, theimperfectly roasted ore is returned to a fresh roast-heap, and the resttrammed to the

LEACH-VATS.

These are 50 in number, 10 having been recently added. The first 40 arefour feet by six feet and four feet deep, the remaining 10 twice aslarge. About two tons of burnt ore is put in the small vats (twice asmuch in the larger ones), half the vats being tilled at one time, andthen enough cold water is turned in to cover the ore. Steam is theninjected beneath the ore, thus boiling the water. After boiling for sometime, the steam is turned off and the water allowed to go cold. Thewater, which after the boiling process turns to a dark red color, isthen drawn off. This water carries the copper in a state of solution.The ore is then boiled a second time, after which the tank residues arethrown out and water kept sprinkling over them. This water collects thecopper still left in the residues, and is then run into a reservoir, andfrom the reservoirs still further on into settling tanks, previous to

PRECIPITATION,

and is then conducted through a system of boxes filled with scrap iron,thus precipitating the copper.

The richer copper liquors which have been drawn from the tanks fire notallowed to run in with that which comes from the dump heaps. This liquoris also run into settling tanks, and from them pumped into four largebarrels, mounted horizontally on friction rollers, to which a very slowmotion is given. These barrels are 18 feet long and six feet six inchesdeep outside measure. They are built very strongly, and are water-tight.Ten tons of scrap iron are always kept in each of these barrels, whichare refilled six times daily, complete precipitation being effected inless than four hours. Each barrel is provided with two safety valves,inserted in the heads, which open automatically to allow the escape ofgas and steam. The precipitation of the copper in the barrels formscopper cement. This cement is discharged from the barrels on to screenswhich hold any lumps of scrap iron which may be discharged with thecement. It is then dried by steam, after which it is conveyed intoanother tank, left to cool, and then placed in bags ready for shipment,as copper cement. The building in which the liquor is treated is themill part of the property, from which they send out 42 tons monthly ofan average of 85 per cent, of copper cement, this being the averageyield of the mine.

There are 23 white men and 40 Chinamen employed at the mine and themill. There are also several wood choppers, etc., on the company'spay-roll. Eight months' supply of ore is always kept on hand, therenow being 12,000 tons roasting. The mine is now paying regular monthlydividends, and everything argues well for the continuance of the same.

* * * * *

SIR WILLIAM THOMSON'S PILE.

The Thomson pile, which is employed with success for putting in actionthe siphon recorder, and which is utilized in a certain number of casesin which an energetic and constant current is needed, is made in twoforms. We shall describe first the one used for demonstration. Eachelement of this (Fig. 1) consists of a disk of copper placed at thebottom of a cylindrical glass vessel, and of a piece of zinc in the formof a grating placed at the upper part, near the surface of the solution.A glass tube is placed vertically in the solution, its lower extremityresting on the copper. Into this tube are thrown some crystals ofsulphate of copper, which dissolve in the liquid, and form a solution ofa greater density than that of the zinc alone, and which, consequently,cannot reach the zinc by diffusion. In order to retard the phenomenon ofdiffusion, a glass siphon containing a cotton wick is placed with one ofits extremities midway between the copper and zinc, and the other ina vessel outside the element, so that the liquid is sucked up slowlynearly to its center. The liquid is replaced by adding from the topeither water or a weak solution of sulphate of zinc.

[Illustration: FIG. 1.--THE THOMSON PILE.(Type for demonstration.)]

The greater part of the sulphate of copper that rises through the liquidby diffusion is carried off by the siphon before reaching the zinc, thelatter being thus surrounded with an almost pure solution of sulphateof copper having a slow motion from top to bottom. This renewal of theliquid is so much the more necessary in that the saturated solution ofsulphate of copper has a density of 1.166, and the sulphate of zincone of 1.445, There would occur, then, a mixture through inversion ofdensities if the solution were allowed to reach a too great amount ofsaturation, did not the siphon prevent such a phenomenon by sucking upthe liquid into the part where the mixture tends to take place. Thechemical action that produces the current is identical with that of theDaniell element.

In its application, this pile is considerably modified in formand arrangement. Each element (Fig 2) consists of a flat woodenhopper-shaped trough, about fifty centimeters square, lined with sheetlead to make it impervious. The bottom is covered with a sheet of copperand above this there is a zinc grate formed of closely set bars thatallow the liquid to circulate. This grate is provided with a rim whichserves to support a second similar element, and the latter a third,and soon until there are ten of the elements superposed to form seriesmounted for tension. The weight of the elements is sufficient to securea proper contact between the zinc and copper of the elements placedbeneath them, such contact being established by means of a band ofcopper cut out of the sheet itself, and bent over the trough.

[Illustration: FIG. 2.--THE THOMSON PILE. (Siphon Recorder Type.)]

On account of the large dimensions of the elements, and the proximityof the two metals, a pile is obtained whose internal resistance is veryfeeble, it being always less than a tenth of an ohm when the pile isin a good state, and the electromotive force being that of the Daniellelement--about 1 08 volts.

Sometimes the zinc is covered with a sheet of parchment which morethoroughly prevents a mixture of the liquids and a deposit of copper onthe zinc. But such a precaution is not indispensable, if care be takento keep up the pile by taking out some of the solution of sulphate ofzinc every day, and adding sulphate of copper in crystals. If the pileis to remain idle for some time, it is better to put it on a shortcircuit in order to use up all the sulphate of copper, the disappearanceof which will be ascertained by the loss of blue color in the liquid. Incurrent service, on the contrary, a disappearance of the blue color willindicate an insufficiency of the sulphate, and will be followed by aconsiderable reduction in the effects produced by the pile.

The great power of this pile, and its constancy, when it is properlykept up, constitute features that are indispensable for the properworking of the siphon recorder--the application for which it was moreespecially designed.

This apparatus has been also employed under some circumstances forproducing an electric light and charging accumulators; but suchapplications are without economic interest, seeing the enormousconsumption of sulphate of copper during the operation of the pile.The use of the apparatus is only truly effective in cases where it isnecessary to have, before everything else, an energetic and exceedinglyconstant current.--_La Nature_.

* * * * *

SIEMENS' TELEMETER

The accompanying cut illustrates a telemeter which was exhibited at theParis Exhibition of Electricity, and which is particularly interestingfrom the fact that it is the first apparatus of this kind. It will beremembered that the object of a telemeter is to make known at any momentwhatever the distance of a movable object, and that, too, by a directreading and without any calculation. In Mr. Siemens' apparatus theproblem is solved in the following manner:

The movable object (very often a vessel) is sighted from two differentstations--two points of the coast, for example--by two differentobservers. The sighting is done with two telescopes, A1 and A2, whichthe observers revolve around a vertical axis by means of two winches, K1and K2, that gear with two trains of clockwork. There is thus constantlyformed a large triangle, having for its apices the movable point sightedand the vertical axes, A1 and A2, of the two telescopes. On anotherhand, at a point situated between the two telescopes, there is a table,T T, that carries two alidades, a1v1, and a2v2, movable around theirvertical axes, a1 and a2. The line, a1 a2, that joins these axes isparallel with that which joins the axes of the two telescopes; and thealidades are connected electrically with the telescopes by a systemsuch that each alidade always moves parallel with the telescope thatcorresponds to it. It follows from this that the small triangle thathas for apices, a1 a2, and the crossing point of the two alidades willalways be like the large triangle formed by the line that joins thetelescopes and the two lines of vision. If, then, we know the ratio ofa1, a2 to A1 A2, it will suffice to measure on one of the alidades thedistance from its axis to the point of crossing in order to know thedistance from the movable object to the axis of the correspondingtelescope. If the table, T T, be covered with a chart giving the spaceover which the ship is moving, so that a1 and a2 shall coincide with thepoints which A1 and A2 represent, the crossing of the threads of thealidades will permit of following on the chart all the ship's movements.In this way there maybe had a powerful auxiliary in coast defence; forall the points at which torpedoes have been sunk may be marked on thechart, and, as soon as the operator at the table finds, by the motionof the alidades, that the ship under observation is directly over atorpedo, he will be able to fire the latter and blow the enemy up.During this time the two observers at A1 and A2 have only to keep theirtelescopes directed upon the vessel that it has been agreed upon towatch.

[Illustration: SIEMENS' ELECTRIC TELEMETER]

In order to obtain a parallelism between the motion of the alidades andthat of the corresponding telescopes, the winch of each of the latter,while putting its instrument in motion, also sets in motion a Siemensdouble-T armature electromagnetic machine. One of the wires of thearmature of this machine, connected to the frame, is always incommunication with the ground at E1 (if we consider, for example, thetelescope to the left), and the other ends in a spring that alternatelytouches two contacts. One of these contacts communicates with thewire, L1 and the other with the wire, L3, so that, when the machine isrevolving, the currents are sent alternately into L1 and L3. These twolatter wires end in a system of electro magnets, M1, provided with apolarized armature. The motions of the latter act, through an anchorescapement, upon a system of wheels. An axle, set in motion by thelatter, revolves one way or the other, according to the direction of thetelescope's motions. This axle is provided with an endless screw thatgears with a toothed sector, and the latter controls the rotatory axisof the alidade. The elements of the toothed wheels and the number ofrevolutions of the armature for a given displacement of the telescopebeing properly calculated, it will be seen that the alidade will be ableto follow all the movements of the latter.

When it is desired to place one of the telescopes in a given position(its position of zero, for example), without acting on the alidade,it may be done by acting directly on the telescope itself without theintermedium of the winch. For such purpose it is necessary to interruptcommunication with the mechanism by pressing on the button, q. If thetelescope be turned to one side or the other of its normal position,in making it describe an angle of 90 deg., it will abut against stops, andthese two positions will permit of determining the direction of thebase.

The alidades themselves are provided with a button which disengages thetoothed sector from the endless screw, and permits of their beingturned to a mark made on the table. A regulating screw permits of thisoperation being performed very accurately. In what precedes, we havesupposed a case in which the movable point is viewed by two observers,and in which the table, T T, is stationed at a place distant from them.In certain cases only two stations are employed. One of the telescopesis then placed over its alidade and moves with it; and the apparatusthus comprehends only a system of synchronous movements.

This telemeter was one of the first that was tried in our militaryports, and gave therein most satisfactory results. The maneuver of thewinch, however, requires a certain amount of stress, and in order thatthe sending of the currents shall be regular, the operator must turn itvery uniformly. This is a slight difficulty that has led to the useof piles, instead of the magneto-electric machine, in the apparatusemployed in France. With such substitution there is need of nothing morethan a movable contact that requires no exertion, and that may be guidedby the telescope itself.--_La Lumiere Electrique_.

* * * * *

PHYSICS WITHOUT APPARATUS.

_Experiment in Static Electricity_.--Take a pipe--a common clay onecosting one cent--and balance it carefully on the edge of a goblet, sothat it will oscillate freely at the least touch, like the beam of ascales. This being done, say to your audience: "Here is a pipe placedon the edge of a goblet; now the question is to make it fall withouttouching it, without blowing against it, without touching the glass,without agitating the air with a fan, and without moving the supportingtable"

[Illustration: CLAY PIPE ATTRACTED BY AN ELECTRIFIED GOBLET.]

The problem thus proposed may be solved by means of electricity. Take agoblet like the one that supports the pipe, and rub it briskly againstyour coat sleeve, so as to electrify the glass through friction. Havingdone this, bring the goblet to within about a centimeter of the pipestem. The latter will then be seen to be strongly attracted, and willfollow the glass around and finally fall from its support.

This curious experiment is a pretty variation of the electric pendulum;and it shows that pipe-clay--a very bad conductor of electricity--favorsvery well the attraction of an electrified body.

Tumblers or goblets are to be found in every house, and a clay pipeis easily procured anywhere. So it would be difficult to producemanifestations of electricity more easily and at less expense than bythe means here described.--_La Nature_.

* * * * *

THE CASCADE BATTERY.

[Footnote: Lately read before the Society of Telegraph Engineers andElectricians.]

By F. HIGGINS.

The battery which I have brought here to-night to introduce to yournotice is of the circulating kind, in which the alimentary fluidemployed passes from cell to cell by gravitation, and maintains theaction of the battery as long as it continues to flow. It cannot,of course, compare with such abundant sources of electricity asdynamo-electric machines driven by steam power, but for purposes inwhich a current of somewhat greater volume and constancy than thatfurnished by the ordinary voltaic batteries is required, it will, Ibelieve, be found in some cases useful. A single fluid is employed, andeach cell is provided with an overflow spout.

The cells are arranged upon steps, in order that the liquid may flowfrom the cell on the topmost step through each successive cell bygravitation [specimen cells were on the table before the audience] tothe reservoir at the bottom. The top and the bottom reservoirs are ofequal capacity, and are fitted with taps. The topmost tap is used toregulate the flow of the solution, and the bottom one to draw it off. Ineach cell two carbon plates are suspended above a quantity of fragmentsof amalgamated zinc. The following is a sectional drawing of thearrangement of the cell:

[Illustration]

A copper wire passes down to the bottom of the cell and makes connectionwith the mercury; this wire is covered with gutta-percha, except whereimmersed in the mercury. The pores of the carbon plates are filledwith paraffin wax. This battery was first employed for the purpose ofutilizing waste solution from bichromate batteries, a great quantity ofwhich is thrown away before having been completely exhausted. This wasteis unavoidable, in consequence of the impossibility of permitting suchbatteries, when employed for telegraphic purposes, to run until completeexhaustion or reduction of the solutions has been effected; thereforesome valuable chemicals have to be sacrificed to insure constancy inworking. The fragments of zinc in this cell were also the remains ofamalgamated zinc plates from the bichromate batteries, and the mercurywhich is employed for securing good metallic connection is soonaugmented by that remaining after the dissolution of the zinc. It willtherefore be seen that not only the solution, but also the zinc andmercury remnants of bichromate batteries are utilized, and at the sametime a considerable quantity of electricity is generated. The cells areseven inches deep and six inches wide, outside, and contain about aquart of solution in addition to the plates. The battery which I employregularly, consisting of 18 cells, is at present working nine permanentcurrent Morse circuits, which previously required 250 telegraphicDaniell cells to produce the same effect, and is capable of working atleast ten times the number of circuits which I have mentioned; but as wedo not happen to have any more of such permanent current Morse circuits,we are unable to make all the use possible of the capabilities of thebattery. The potential of one cell is from 1.9 to 2 volts with strongsolution, and the internal resistance varies from 0.108 to 0.170 of anohm with cells of the size described. In order to test the constancy ofthe battery, a red heat was maintained in a platinum-iridium wire by thecurrent for six weeks, both day and night.

The absence or exhaustion of the zinc in any one cell in a battery isindicated by the appearance of a red insoluble chromic salt of mercury,in a finely divided state, floating in the faulty cell. It is thennecessary to drop in some pieces of zinc. The state of the zinc supplymay also be ascertained at any time by feeling about in the cells with astick. When not required, the battery may be washed by simply chargingthe top reservoir with water, and leaving it to circulate in the usualmanner, or the solution may be withdrawn from each cell by a siphon. Avery small flow of the solution is sufficient to maintain the requiredcurrent for telegraphic working, but if the flow be stopped altogetherfor a few hours, no difference is observed in the current, although whenthe current is required to be maintained in a conductor of a few ohmsresistance, as in heating a platinum wire, it is necessary that thecirculation be maintained [heating a piece of platinum ribbon]. Thebattery furnishing the current for producing the effect you now see isof five cells, and as that number is reduced down to two, you see a glowstill appears in the platinum. The platinum strip employed was 5 incheslong and 1/8 inch wide, its resistance being 0.42 ohm, cold. That givesan idea of the volume of current flowing. I have twelve electro magnetsin printing instruments joined up on the table, and [joining up thebattery] you see that the two cells are sufficient to work them. Thetwelve electro-magnets are being worked (by the two cells) in multiplearc at the same time. The current from the cells which heated theplatinum wire is amply sufficient to magnetize a Thomson recorder. Ihave maintained five inches of platinum ribbon in a red hot state fortwo hours, in order to make sure that the battery I was about to bringbefore you was in good order. The cost of working such a battery whenwaste solution cannot be obtained, and it is necessary to use speciallyprepared bichromate solution, is about 21/4d. per cell per day, with acurrent constantly active in a Thomson recorder circuit, or a resistanceof 11/2 ohms per cell; but if only occasionally used, the same quantity ofsolution will last several weeks.

A comparison of this with another form of constant battery, the Daniell,as used in telegraphy, shows that six of these cells, with a totalelectromotive force of 12 volts and an internal resistance of 0.84 ofan ohm, cannot be replaced by less than 71 batteries of 10 cells each,connected in multiple arc, or for quantity. This result, however largeit may appear, is considerably below that which may be obtained whenworking telegraphic lines. A current of 0.02 weber, or ampere, will workan ordinary sounder or direct writing Morse circuit; the cascade batteryis capable of working 100 such circuits at the same time, while thecombined resistance of that number of lines would not be below that inwhich it is found that the battery is constant in action.

Objection may be made to the arrangement of the battery on the score ofwaste of zinc by local action, because of the electro positive metalbeing exposed to the chromic liquid; but if the battery be out of actionand the circulation stopped, the zinc amalgam is protected by theimmobility of the liquid and the formation of a dense layer of sulphateof zinc on its surface. When in action, that effect is neutralized fromthe fact that carbon in chromic acid is more highly electro-negativethan the chromate of mercury formed upon the zinc amalgam, and whichappears to be the cause of the dissolution of the zinc even whenamalgamated in the presence of chromic acid. The solution may berepeatedly passed through the battery until the absence of thecharacteristic warmth of color of chromic acid indicates its completeexhaustion. During a description before the Society of thermo-electricbatteries some time ago, Mr. Preece mentioned that five of thethermopiles which were being tried at the Post-Office were doing thework of 2,535 of the battery cells previously employed. Thirty ofthe cascade cells would have about the same potential as five suchthermopiles, but would supply three and a half times the current, and becapable of doing the work of 8,872 cells if employed upon the universalbattery system in the same manner as the thermo batteries referred to.

Although this battery will do all that is required for a Thomsonrecorder or a similar instrument much more cheaply in this country thanthe tray battery, and with half the number of cells, I do not think itwould be the case in distant countries, on account of the difficulty andcost of transport. A solid compound of chromic and sulphuric acids couldbe manufactured which would overcome this difficulty, if permanentmagnetic fields for submarine telegraphic instruments continue to beproduced by electric vortices. In conclusion, and to enable comparisonsto be made, I may mention that the work this battery is capable ofperforming is 732,482 foot pounds, at a total cost of 1s. 6d.

* * * * *

[FROM THE SCHOOL JOURNAL.]

PERFECTLY LOVELY PHILOSOPHY.

CHARACTERS: Laura and Isabel, dressed very stylishly, both with hats on.Enter hand in hand.

_Laura_. My dear Isabel, I was so afraid you would not come. I waitedat that horrid station a full half hour for you. I went there early onpurpose, so as to be sure not to miss you.

_Isabel_. Oh, you sweet girl!

_L_. Now, sit right down; you must be tired. Just lay your hat there onthe table, and we'll begin to visit right off. (_Both lay their hats onthe table and stand near by_.)

_I_. And how have you been all the ages since we were together atBoston?

_L_. Oh, well, dear; those were sweet old school days, weren't they. Howare you enjoying yourself now? You wrote that you were taking lessons inphilosophy. Tell me how you like it. Is it real sweet?

_I_ Oh, those I took in the winter were perfectly lovely! It was aboutscience, you know, and all of us just doled on science.

_L_. It must have been nice. What was it about?

_I_. It was about molecules as much as anything else, and molecules arejust too awfully nice for anything. If there's anything I really enjoy,it's molecules.

_L_. Oh, tell me about them, dear. What are molecules?

_I_. They are little wee things, and it takes ever so many of them, youknow. They are so sweet! Do you know, there isn't anything but that'sgot a molecule in it. And the professors are so lovely! They explainedeverything so beautifully.

_L_. Oh, how I'd like to have been there!

_I_. You'd have enjoyed it ever so much. They teach protoplasm, too,and if there's one thing that is too sweetly divine, it's protoplasm. Ireally don't know which I like best, protoplasm or molecules.

_L_. Tell me about protoplasm. I know I should adore it!

_I_. 'Deed you would. It's just too sweet to live. You know it's abouthow things get started, or something of that kind. You ought to haveheard the professors tell about it. Oh. dear! (_Wipes her eyes withhandkerchief_) The first time he explained about protoplasm there wasn'ta dry eye in the room. We all named our hats after the professors. Thisis a Darwinian hat. You see the ribbon is drawn over the crown this way(_takes hat and illustrates_), and caught with a buckle and bunch offlowers. Then you turn up the side with a spray of forget me-nots.

_L_. Oh, how utterly sweet! Do tell me some more of science. I adore italready.

_I_. Do you, dear? Well, I almost forgot about differentiation. I amreally and truly positively in love with differentiation. It's differentfrom molecules and protoplasms, but it's every bit as nice. And ourprofessor! You should hear him enthuse about it; he's perfectly bound upin it. This is a differentiation scarf--they've just come out. Allthe girls wear them--just on account of the interest we take indifferentiation.

_L_. What is it, anyway?

_I_. Mull trimmed with Languedoc lace, but--

_L_. I don't mean that--the other.

_I_. Oh, differentiation! That's just sweet. It's got something todo with species. And we learn all about ascidians, too. They are thedivinest things! If I only had an ascidian of my own! I wouldn't askanything else in the world.

_L_. What do they look like, dear? Did you ever see one?

_I_. Oh, no; nobody ever did but the poor dear professors; but they'resomething like an oyster with a reticule hung on its belt. I think theyare just _too_ lovely for anything.

_L_. Did you learn anything else besides?

_I_. Oh, yes. We studied common philosophy, and logic, and metaphysics,and a lot of those ordinary things, but the girls didn't care anythingabout those. We were just in ecstasies over differentiations, andmolecules, and the professor, and protoplasms, and ascidians. I don'tsee why they put in those common branches; we couldn't hardly endurethem.

_L_. (_Sighs_.) Do you believe they'll have a course like that nextyear?

_I_. I think may be they will.

_L_. Dear me! There's the bell to dress for dinner. How I wish I couldstudy those lovely things!

_I_. You must ask your father if you can't spend the winter in Bostonwith me. I'm sure there'll be another course of Parlor Philosophy nextwinter. But how dreadful that we must stop talking about it now to dressfor dinner! You are going to have company, you said; what shall youwear, dear?

_L_. Oh, almost anything. What shall you?

(_Exeunt arm in arm_.)

* * * * *

THE PROPOSED DUTCH INTERNATIONAL COLONIAL AND GENERAL EXPORT EXHIBITION.

The Amsterdam International Exhibition, the opening of which has beenfixed for May 1, 1883, is now in way of realization. This exhibitionwill present a special interest to all nations, and particularly totheir export trade. Holland, which is one of the great colonial powers,proposes by means of this affair to organize a competition between thevarious colonizing nations, and to contribute thus to a knowledge ofthe resources of foreign countries whose richness of soil is theirfundamental power.

The executive committee includes the names of some of the most prominentpersons of the Netherlands: M. Cordes, president; M. de Clercq,delegate; M. Kappeyne van di Coppello, secretary; and M. Agostini,commissary general.

The exhibition will consist of five great divisions, to wit: 1. AColonial exhibition. 2. A General Export exhibition. 3. A Retrospectiveexhibition of Fine Arts and of Arts applied to the Industries. 4.Special exhibitions. 5. Lectures and Scientific Reunions.

The colonial part forms the base of the exhibition, and will be devotedto a comparative study of the different systems of colonizationand colonial agriculture, as well as of the manners and customs ofultramarine peoples. In giving an exact idea of what has been done, itwill indicate what remains to be done from the standpoint of a generaldevelopment of commerce and manufactures. Such is the programme of thefirst division.

The second division will include everything that relates to the exporttrade.

The third division will be reserved for works of art dating back fromthe most remote ages.

The fourth division will be devoted to temporary exhibitions, such asthose of horticultural and agricultural products, etc.

The fifth division will constitute the intellectual part, so to speak,of the exhibition. It will be devoted to lectures, and to scientificmeetings for the discussion of questions relating to teaching, to thearts, to the sciences, to hygiene, to international jurisprudence, andto political economy. Questions of colonial economy will naturallyoccupy the first rank.

As will be seen, the programme of this grand scheme organized by theNetherlands government is a broad one; and, owing the experienceacquired in recent universal exhibitions, especially that of Paris in1878, very happy results may be expected from it.

At present, we give an illustration showing the general plan of theexhibition. In future, in measure as the work proceeds, we shall be ableto give further details.--_Le Genie Civil_.

* * * * *

NEW METHOD OF DETECTING DYES ON YARNS AND TISSUES.

By JULES JOFFRE.

The reagents employed are a solution of caustic potassa in ten partsof water; hydrochloric acid diluted with an equal bulk of water, oroccasionally concentrated; nitric acid, ammonia, ferric sulphate, anda concentrated solution of tin crystals. The most convenient method ofoperating is to steep small portions of the cloth under examination in alittle of the reagent placed at the bottom of a porcelain capsule. Thebits are then laid on the edge of the capsule, when the changes of colorwhich they have undergone may be conveniently observed. It is useful tosubmit to the same reagents simultaneously portions of cloth dyed in aknown manner with the wares which are suspected of having been used indyeing the goods under examination.

RED COLORS.

By the action of caustic potassa, the reds are divided into four groups:1, those which turn to a violet or blue; 2, those which turn brown;3, those which are changed to a light yellow or gray; 4, those whichundergo little or no change.

The first group comprises madder, cochineal, orchil, alkanet, andmurexide. Madder reds are turned to an orange by hydrochloric acid,while the three next are not notably affected. Cochineal is turned bythe potassa to a violet-red, orchil to a violet-blue, and alkanet to adecided blue. Lac-dye presents the same reactions as cochineal, buthas less brightness. Ammoniacal cochineal and carmine may likewise bedistinguished by the tone of the reds obtained.

A characteristic of madder reds is that, after having been turned yellowby hydrochloric acid, they are rendered violet on treatment with milkof lime. A boiling soap-lye restores the original red, though somewhatpaler. Artificial alizarine gives the same reaction. Turkey-reds,however, are quite unaffected by acid. Garancine and garanceux reds, iftreated first with hydrochloric acid and then with milk of lime, turn toa dull blue.

Madder dyes are sometimes slow in being turned to a violet by potassa,and this shade when produced is often brownish. They might thus beconfounded with the dyes of the fourth group, i.e., rosolic acid,coralline, eosine, and coccine. None of these colors gives thecharacteristic reaction with milk of lime and boiling soap-lye. Ifplunged in milk of lime, they resume their rose or orange shades, whilethe madder colors become violet. Murexide is turned, by potassa, grayin its light shades and violet in its dark ones. It might, then, beconfounded with orchil, but it is decolorized by hydrochloric acid,which leaves orchil a red. Moreover, it is turned greenish by stannouschloride.

A special character of this dye (murexide) is the presence of mercury,the salts of which serve as mordants for fixing it, and may be detectedby the ordinary reagents.

The second group comprises merely sandal wood or sanders red, whichturns to a brown. On boiling it with copperas it becomes violet, whileon boiling with potassium dichromate it changes to a yellowish brown.

The third group includes safflower, magenta, and murexide (lightshades). If the action of the potassa is prolonged the (soft) red woodsenter into this group. Safflower turns yellow by the action of potassa,and the original rose shade is not restored by washing with water.Hydrochloric acid turns it immediately yellow. Citric acid has noaction. Magenta is completely decolorized by potassa, but a prolongedwashing in water reproduces the original shade. This reaction is commonto many aniline colors. These decolorations and recolorations are easilyproduced in dark shades, while in very light shades they are less easilyobserved, because there is always a certain loss of color. Stannouschloride turns magenta reds to a violet. Hydrochloric acid renders themyellowish brown (afterward greenish?). Water restores the purple redshade.

The fourth group comprises saffranine, azo-dinaphthyldiamine, rosolicacid, coralline, pure eosine and cosine modified by a salt of lead,coccina, artificial ponceau, and red-wood.

Saffranine is detected by the action of hydrochloric acid, which turnsit to a beautiful blue; the red color is restored by washing in water.Azo-dinaphthyl diamine is recognized by its peculiar orange cast, and isturned by hydrochloric acid to a dull, dirty violet. Rosolic acid andcoralline, as well as eosine, are turned by hydrochloric acid to anorange-yellow: the two former are distinguished from eosine by theirshade, which inclines to a yellow. Potassa turns rosolic acid andcoralline from an orange-red to a bright red, while it produces nochange in eosine. If the action of potassa is prolonged, modified eosineis blackened in consequence of the decomposition of the wool, thesulphur of which forms lead sulphide. Coccine becomes of a lightlemon-yellow on treatment with hydrochloric acid. Washing with waterrestores the original shade. It affords the same reactions as eosine,but its tone is more inclined to an orange.

Artificial ponceau does not undergo any change on treatment withhydrochloric acid, and resists potash. Red wood shades are turned towarda gooseberry-red by hydrochloric acid, especially if strong. This lastreaction not being very distinct, red-wood shades might be mistakenfor those of artificial ponceau but for the superior brightness of thelatter. If the action of potassa is prolonged, the red-wood shadesare decolorized, and a washing with water then bleaches the tissue.Rocelline affords the same reactions as artificial ponceau, but ifsteeped in a concentrated solution of stannous chloride it is in timecompletely discharged, which is not the case with artificial ponceau.

VIOLET COLORS.

Violets are divided into two groups: those affected by potassa, andthose upon which it has no action. The first group embraces logwood,orchil, alkanet, and aniline violets, including under the latter termPerkin's violet, (probably the original "mauve"), dahlia, Parme ormagenta violet, methyl, and Hofmann's violets. The action of potassagives indications for each of these violets. Logwood violet is browned;that of orchil, if slightly reddish, is turned to a blue-violet; that ofalkanet is modified to a fine blue. Lastly, Perkin's mauve, dahlia, andmethyl violet become of a grayish brown, which may be re-converted intoa fine violet by washing in abundance of water. When the shades arevery heavy, this grayish brown is almost of a violet-brown, so that theviolets might seem to be unaltered.

The action of hydrochloric acid distinguishes these colors better stillif the aid of ammonia is called in for two cases.

The acid turns logwood violet to a fine red, and equally reddens orchilviolet. But the two colors cannot be confounded, first, because the twoviolet shades are very distinct, that of orchil being much the brighter;and secondly, because ammonia has no action on logwood violet, while itturns orchil violet, if at all reddish, to a blue shade. Hydrochloricacid, whether dilute or concentrated, is without action on alkanetviolet. If the acid is dilute, it is equally without action on Perkin'sviolet and dahlia. If it is strong, it turns them blue, and even greenif in excess. Hofmann's violet turns green even with dilute acid, butprolonged washing restores the original violet shade. Dahlia gives amore blue shade than Perkin's mauve. The action of acid is equallycharacteristic for methyl violet. It becomes green, then yellow. Washingin water re-converts it first to a green, and then to a violet.

The second group includes madder violet, cochineal violet, and thecompound violet of cochineal and extract of indigo. These three dyes arethus distinguished: Hydrochloric acid turns the madder violet-orange,slightly brownish, or a light brown, and it affords the characteristicreaction of the madder colors described above under reds. Cochinealviolets are reddened. Sometimes they are decolorized, and become finallyyellow, but do not pass through a brown stage.

The compound violet of cochineal and extract of indigo presents thischaracteristic reaction, that if boiled with very weak solution ofsodium carbonate the liquid becomes blue, rather greenish, while thecloth becomes a vinous-red--_Moniteur Scientifique.--Chem. News._

* * * * *

CHEVALET'S CONDENSO-PURIFIER FOR GAS.

The condenso-purifier shown in the accompanying cut operates asfollows: Water is caused to flow over a metallic plate perforated withinnumerable holes of from one to three millimeters in diameter, andthen, under this disk, which is exactly horizontal, a current of gas isintroduced. Under these circumstances the liquid does not traverse theholes in the plate, but is supported by the gas coming in an oppositedirection. Provided that the gas has sufficient pressure, it bubbles upthrough the water and becomes so much the more divided in proportion asthe holes are smaller and more numerous.

The gas is washed by traversing the liquid, and freed from the tar andcoal-dust carried along with it; while, at the same time, the ammoniathat it contains dissolves in the water, and this, too, so much thebetter the colder the latter is. This apparatus, then, permits ofobtaining two results: a mechanical one, consisting in the stoppage ofthe solid matters, and a chemical one, consisting in the stoppage of thesoluble portions, such as ammonia, sulphureted hydrogen, and carbonicacid.

[Illustration: FIG. 1.--CONDENSO-PURIFIER FOR GAS. (Elevation.)]

The condenso-purifier consists of three perforated diaphragms, placedone over the other in rectilinear cast-iron boxes. These diaphragms aremovable, and slide on projections running round the interior of theboxes. In each of the latter there is an overflow pipe, g, that runs tothe box or compartment below, and an unperforated plate, f, that slidesover the diaphragm so as to cover or uncover as many of the holes as maybe necessary. A stream of common water runs in through the funnel, e,over the upper diaphragm, while the gas enters the apparatus through thepipe, a, and afterward takes the direction shown by the arrows.Reaching the level of the overflow, the water escapes, fills the lowercompartment, covers the middle diaphragm, then passes through the secondoverflow-pipe to cover the lower diaphragm, next runs through theoverflow-pipe of the third diaphragm on to the bottom of the purifier,and lastly makes its exit, through a siphon. A pressure gauge, having aninlet for the gas above and below, serves for regulating the pressureabsorbed for each diaphragm, and which should vary between 0.01 and0.012 of a meter.

The effect of this purifier is visible when the operation is performedwith an apparatus made externally of glass. The gas is observed to enterin the form of smoke under the first diaphragm, and the water to becomediscolored and tarry. When the gas traverses the second diaphragm, it isobserved to issue from the water entirely colorless, while the latterbecomes slightly discolored, and finally, when it traverses the thirddiaphragm, the water is left perfectly limpid.

Two diaphragms have been found sufficient to completely remove the solidparticles carried along by the gas, the third producing only a chemicaleffect.

This apparatus may replace two of the systems employed in gas works: (1)mechanical condensers, such as the systems of Pelouze & Audouin, andof Servier; and (2) scrubbers of different kinds and coke columns.Nevertheless, it is well to retain the last named, if the gas works havethem, but to modify their work.

[Illustration: FIG. 2.--PLAN VIEW WITH BY-PASS.]

This purifier should always be placed directly after the condensers, andis to be supplied with a stream of pure water at the rate of 50 litersof water per 1,000 cubic meters of gas. Such water passes only once intothe purifier, and issues therefrom sufficiently rich in ammonia to betreated.

If there are coke columns in the works, they are placed after thepurifier, filled with wood shavings or well washed gravel, and thensupplied with pure cold water in the proportion stated above. The waterthat flows from the columns passes afterward into the condenso-purifier,where it becomes charged with ammonia, and removes from the gas the tarthat the latter has carried along, and then makes its exit and goes tothe decanting cistern.

In operating thus, all the remaining ammonia that might have escaped thecondenso-purifier is removed, and the result is obtained without pumpsor motor, with apparatus that costs but little and does not occupy muchspace. The advantages that are derived from this, as regards sulphateof ammonia, are important; for, on treating ammoniacal waters withcondensers, scarcely more than four to five kilogrammes of the sulphateare obtained per ton of coal distilled, while by washing the gasperfectly with the small quantity of water indicated, four to fivekilogrammes more can be got per 1,000 kilogrammes of coal, or a total ofeight to ten kilogrammes per ton.

When the gas is not washed sufficiently, almost all of the ammoniacondenses in the purifying material.

The pressure absorbed by the condenso purifier is from ten to twelvemillimeters per washing-diaphragm. In works that are not provided withan extractor, two diaphragms, or even a single one, are employed when itis desired simply to catch the tar.

The apparatus under consideration was employed in the St. Quentingas works during the winter of 1881-1882, without giving rise to anyobstruction; and, besides, it was found that by its use there might beavoided all choking up of the pipes at the works and the city mainsthrough naphthaline.

In cases of obstruction, it is very easy to take out the perforateddiaphragms; this being done by removing the bolts from the piece thatholds the register, f, and then removing the diaphragm and putting inanother. This operation takes about ten minutes. The advantages of sucha mounting of the diaphragms is that it allows the gas manufacturer toemploy (and easily change) the number of perforations that he finds bestsuited to his needs.

These apparatus are constructed for productions of from 1,000 to 100,000cubic meters of gas per twenty four hours. They have been appliedadvantageously in the washing of smoke from potassa furnaces, in orderto collect the ammonia that escapes from the chimneys. In one of suchapplications, the quantity of gas and steam washed reached a millioncubic meters per twenty-four hours.--_Revue Industrielle._

* * * * *

ARTIFICIAL IVORY.

It is said that artificial ivory of a pure white color and very durablehas been manufactured by dissolving shellac in ammonia, mixing thesolution with oxide of zinc, driving off ammonia by heating, powdering,and strongly compressing in moulds.

* * * * *

CREOSOTE IMPURITIES.

[Footnote: Read at the meeting of the American PharmaceuticalAssociation held at Niagara Falls. 1882.]

By Prof. P. W. BEDFORD.

The object of this query can be but one, namely, to inquire whether thewood creosote offered for sale is a pure article, or not; and if not,what is the impurity present?

The relative commercial value of the articles sold as coal tar creosoteand wood creosote disposes of the question as to the latter beingpresent in the former article, and we are quite certain that the cheapvariety is nothing more or less than a phenol or carbolic acid. Woodcreosote, it has been frequently stated, is adulterated with coal tarcreosote, or phenol. The object of my experiments has been to prove theidentity of wood creosote and its freedom from phenol. The followingtests are laid down in various works as conclusive evidence of itspurity, and each has been fully tried with the several samples of woodcreosote to prove their identity and purity, and also with phenol, soldas commercial creosote or coal tar creosote, and for comparison withmixtures of the two, that even small percentages of admixture might beidentified, should such exist in the wood creosote of the market.

The following tests were used:

1. Equal volumes of anhydrous glycerine and wood creosote make a turbidmixture, separating on standing. _Phenol dissolves_. If three volumesof water be added, the separation of the wood creosote is immediate._Phenol remains in permanent solution_.

2. One volume of wood creosote added to two volumes of glycerine; theformer is not dissolved, but separates on standing. _Phenol dissolves_.

3. Three parts of a mixture containing 75 per cent, of glycerine and25 of water to 1 part of wood creosote show no increase of volume ofglycerine, and wood creosote separates. _Phenol dissolves, and formsa clear mixture_. Were any phenol present in the wood creosote, theincrease in the volume of the glycerine solution, if in a graduatedtube, would distinctly indicate the percentage of phenol present.

5. A 1 per cent, solution of wood creosote. Take of this 10 cubiccentimeters, add 1 drop of a test solution of ferric chloride; anevanescent blue color is formed, passing quickly into a red color._Phenol gives a permanent blue color_.

6. Collodion or albumen with an equal bulk of wood creosote makes aperfect mixture without coagulation. _Phenol at once coagulates into amore or less firm mass or clot_.

All tests enumerated above were repeatedly tried with four samples ofwood creosote sold as such; one a sample of Morson's, one of Merck's,one evidently of German origin, but bearing the label and capsule of anAmerican manufacturer, and one of unknown origin, but sold as beech-woodcreosote (German), and each proved to be _pure wood creosote_.

Two samples of commercial creosote which, from the low cost, were knownto be of coal tar origin gave the negative tests, showing that they werephenol.

Corroborative experiments were made by mixing 10 to 20 per cent, ofphenol with samples of the beechwood creosote, but in every case each ofthe tests named showed the presence of the phenol.

The writer on other occasions applied single tests (the collodion test)to samples of beechwood creosote that he had an opportunity of procuringsmall specimens of, and satisfied himself that they were pure. Theconclusion is that the wood creosote of the market of the present timeis in abundant supply, is of unexceptionable quality, and reasonable inprice, so that there is no excuse for the substitution of the phenolcommonly sold for it. When it is directed for use for internaladministration (the medicinal effect being entirely dissimilar), woodcreosote only should be dispensed.

The general sales of creosote by the pharmacist are in small quantitiesas a toothache remedy, and phenol has the power of coagulating albumen,which effectually relieves the suffering. Wood creosote does notcoagulate albumen, and is, therefore, not as serviceable. This is,perhaps, the reason that it has become, in a great measure, supplantedin general sale by the coal tar creosote, to say nothing of the argumentof a lower cost.

* * * * *

REMEDY FOR SICK HEADACHE.

Surgeon Major Roehring, of Amberg, reports, in No. 32 of the _Allg. Med.Centr. Zeit_., April 22, 1882, a case of headache of long standing,which he cured by salicylate of sodium, which confirms the observationsof Dr. Oehlschlager, of Dantzig, who first contended that we possessedin salicylic acid one of the most reliable remedies for neuralgia. Thiscannot astonish us if we remember that the action of salicylic acid is,in more than one respect, and especially in its influence on the nervouscenters, analogous to quinine.

While out with the troops on maneuver, Dr. Roehring was called to visitthe sixteen-year old son of a poor peasant family in a neighboringvillage. The boy, who gave all evidences of living under bad hygienicsurroundings, but who had shown himself very diligent at school, hadbeen suffering, from his sixth year, several days every week from themost intense headache, which had not been relieved by any of the manyremedies tried for this purpose. A careful examination did not revealany organic lesion or any cause for the pain, which seemed to beneuralgic in character, a purely nervous headache. Roehring had justbeen reading the observations of Oehlschlager, and knowing, from thenames of the physicians who had been already attending the poor boy,that all the common remedies for neuralgia had been given a fair trial,thought this a good opportunity to test the virtue of salicylate ofsodium. He gave the boy, who, in consequence of the severity of thepain, was not able to leave his bed, ten grains of the remedy everythree hours, and was surprised to see the patient next day in his tentand with smiling face. The boy admitted that he for years had not beenfeeling so well as he did then. The remedy was continued, but in lessfrequent doses, for a few days longer; the headache did not return.Several months later Dr. Roehring wrote to the school-teacher of theboy, and was informed that the latter had, during all this time,been totally free of his former pain, that he was much brighter thanformerly, and evidently enjoying the best of health.

It may be worth while to give the remedy a more extensive trial, and themore so as we are only too often at a loss what to do in stubborn casesof so-called nervous headache.--_The Medical and Surgical Reporter_.

* * * * *

SUNLIGHT AND SKYLIGHT AT HIGH ALTITUDES.

At the Southampton meeting of the British Association, Captain Abneyread a paper in which he called attention to the fact that photographstaken at high altitudes show skies that are nearly black by comparisonwith bright objects projected against them, and he went on to show thatthe higher above the sea level the observer went, the darker the skyreally is and the fainter the spectrum. In fact, the latter shows butlittle more than a band in the violet and ultraviolet at a height of8,500 feet, while at sea-level it shows nearly the whole photographicspectrum. The only reason of this must be particles of some reflectingmatter from which sunlight is reflected. The author refers this towatery stuff, of which nine-tenths is left behind at the altitude atwhich be worked. He then showed that the brightness of the ultra-violetof direct sunlight increased enormously the higher the observer went,but only to a certain point, for the spectrum suddenly terminated about2,940 wave-length. This abrupt absorption was due to extra-atmosphericcauses and perhaps to space. The increase in brightness of theultra-violet was such that the usually invisible rays, L, M, N, could bedistinctly seen, showing that the visibility of these rays dependedon the intensity of the radiation. The red and ultra-red part of thespectrum was also considered. He showed that the absorption lines werepresent in undiminished force and number at this high altitude, thusplacing their origin to extra-atmospheric causes. The absorption fromatmospheric causes of radiant enemy in these parts he showed was dueto "water-stuff," which he hesitated to call aqueous vapor, since thebanded spectrum of water was present, and not lines. The B and A line healso stated could not be claimed as telluric lines, much less as due toaqueous vapor, but must originate between the sun and our atmosphere.The author finally confirmed the presence of benzine and ethyl in thesame region. He had found their presence indicated in the spectrum atsea-level, and found their absorption lines with undiminished intensityat 8,500 feet. Thus, without much doubt, hydrocarbons must exist betweenour atmosphere and the sun, and, it may be, in space.

Prof. Langley, following Capt. Abney, observed: The very remarkablepaper just read by Captain Abney has already brought informationupon some points which the one I am about, by the courtesy of theAssociation, to present, leaves in doubt. It will be understood thenthat the references here are to his published memoirs only, and not towhat we have just heard.

The solar spectrum is so commonly composed to have been mapped withcompleteness, that the statement that much more than one-half its extentis not only unmapped but nearly unknown, may excite surprise. Thisstatement is, however, I think, quite within the truth, as to thatalmost unexplored region discovered by the elder Herschel, which, lyingbelow the red and invisible to the eye, is so compressed by the prismthat, though its aggregate heat effects have been studied through thethermopile, it is only by the recent researches of Capt. Abney that wehave any certain knowledge of the lines of absorption there, even inpart. Though the last-named investigator has extended our knowledge ofit to a point much beyond the lowest visible ray, there yet remains astill remoter region, more extensive than the whole visible spectrum,the study of which has been entered on at Alleghany, by means of thelinear bolometer.

The whole spectrum, visible and invisible, is powerfully affected by theselective absorption of our atmosphere and that of the sun; and we mustfirst observe that could we get outside our earth's atmospheric shell,we should see a second and very different spectrum, and could weafterward remove the solar atmosphere also, we should have yet a third,different from either. The charts exhibited show:

1st. The distribution of the solar energy as we receive it, at theearth's surface, throughout the entire invisible as well as visibleportion, both on the prismatic and normal scales. This is what I haveprincipally to speak of now, but this whole first research is butincidental to others upon the spectra before any absorption, whichthough incomplete, I wish to briefly allude to later. The other curvesthen indicate:

2d. The distribution of energy before absorption by our own atmosphere.

3d. This distribution at the photosphere of the sun. The extent ofthe field, newly studied, is shown by this drawing [chart exhibited].Between H in the extreme violet, and A in the furthest red, lies thevisible spectrum, with which we are familiar, its length being about4,000 of Angstrom's units. If, then, 4,000 represent the length of thevisible spectrum, the chart shows that the region below extends through24,000 more, and so much of this as lies below wave-length 12,000, Ithink, is now mapped for the first time.

[Illustration: FIG. 1.--PRISMATIC SPECTRUM.]

We have to pi = 12,000 relatively complete photographs, published byCapt. Abney, but, except some very slight indications by Lamansky,Desains, and Mouton, no further guide.

Deviations being proportionate to abscissae, and measured solar energiesto ordinates, we have here (1) the distribution of energy in theprismatic, and (2) its distribution in the normal spectrum. The totalenergy is in each case proportionate to the area of the curve (the twovery dissimilar curves inclosing the same area), and on each, if thetotal energy be roughly divided into four parts, one of these willcorrespond to the visible, and three to the invisible or ultra-red part.The total energy at the ultra violet end is so small, then, as to behere altogether negligible.

We observe that (owing to the distortion introduced by the prism) themaximum ordinate representing the heat in the prismatic spectrum is, asobserved by Tyndall, below the red, while upon the normal scale thismaximum ordinate is found in the orange.

I would next ask your attention to the fact that in either spectrum,below pi = 12,000 are most extraordinary depressions and interruptionsof the energy, to which, as will be seen, the visible spectrum offersno parallel. As to the agent producing these great gaps, which sostrikingly interrupt the continuity of the curve, and, as you see,in one place, cut it completely into two, I have as yet obtained noconclusive evidence. Knowing the great absorption of water vapor in thislowest region, as we already do, from the observations of Tyndall, itwould, _a priori_, seem not unreasonable to look to it as the cause. Onthe other hand, when I have continued observations from noon to sunset,making successive measures of each ordinate, as the sinking sun sent itsrays through greater depths of absorbing atmosphere, I have not foundthese gaps increasing as much as they apparently should, if due to aterrestrial cause, and so far as this evidence goes, they might berather thought to be solar. But my own means of investigation are not sowell adapted to decide this important point as those of photography, towhich we may yet be indebted for our final conclusion.

[Illustration: FIG. 2.--NORMAL SPECTRUM. (At sea level.)]

I am led, from a study of Capt. Abney's photographs of the regionbetween pi = 8,000 and pi = 12,000, to think that these gaps areproduced by the aggregation of finer lines, which can best bediscriminated by the camera, an instrument which, where it can be usedat all, is far more sensitive than the bolometer; while the latter, Ithink, has on the other hand some advantage in affording direct andtrustworthy measures of the amount of energy inhering in each ray.

One reason why the extent of this great region has been so singularlyunderestimated, is the deceptively small space into which it appears tobe compressed by the distortion of the prism. To discriminate betweenthese crowded rays, I have been driven to the invention of a specialinstrument. The bolometer, which I have here, is an instrument dependingupon principles which I need not explain at length, since all presentmay be presumed to be familiar with the success which has beforeattended their application in another field in the hands of thePresident of this Association.

I may remark, however, that this special construction has involved veryconsiderable difficulties and long labor. For the instrument here shown,platinum has been rolled by Messrs. Tiffany, of New York, into sheets,which, as determined by the kindness of Professor Rood, reach thesurprising tenuity of less than one twenty-five-thousandth of an Englishinch (I have also iron rolled to one fifteen-thousandth inch), and fromthis platinum a strip is cut one one-hundred-and-twenty-fifth of an inchwide. This minute strip, forming one arm of a Wheatstone's bridge, andthus perfectly shielded from air currents, is accurately centered bymeans of a compound microscope in this truly turned cylinder, and thecylinder itself is exactly directed by the arms of this Y.

The attached galvanometer responds readily to changes of temperature, ofmuch less than one-ten-thousandth degree F. Since it is one and the samesolar energy whose manifestations we call "light" or "heat," accordingto the medium which interprets them, what is "light" to the eye is"heat" to the bolometer, and what is seen as a dark line by the eye isfelt as a cold line by the sentient instrument. Accordingly, if linesanalogous to the dark "Fraunhofer lines" exist in this invisible region,they will appear (if I may so speak) to the bolometer as cold bands, andthis hair-like strip of platina is moved along in the invisible part ofthe spectrum till the galvanometer indicates the all but infinitesimalchange of temperature caused by its contact with such a "cold band." Thewhole work, it will be seen, is necessarily very slow; it is in fact along groping in the dark, and it demands extreme patience. A portion ofits results are now before you.

The most tedious part of the whole process has been the determination ofthe wave-lengths. It will be remembered that we have (except through thework of Capt. Abney already cited, and perhaps of M. Mouton) no directknowledge of the wave-lengths in the infra-red prismatic spectrum, buthave hitherto inferred them from formulas like the well-known one ofCauchy's, all which known to me appear to be here found erroneous by thetest of direct experiment, at least in the case of the prism actuallyemployed.

I have been greatly aided in this part of the work by the remarkableconcave gratings lately constructed by Prof. Rowland, of Baltimore, oneof which I have the pleasure of showing you. [Instrument exhibited.]

The spectra formed by this fall upon a screen in which is a fine slit,only permitting nearly homogeneous rays to pass, and these, which maycontain the rays of as many as four overlapping spectra, are next passedthrough a rock-salt or glass prism placed with its refracting edgeparallel to the grating lines. This sorts out the different narrowspectral images, without danger of overlapping, and after their passagethrough the prism we find them again, and fix their position by means ofthe bolometer, which for this purpose is attached to a special kind ofspectrometer, where its platinum thread replaces the reticule of theordinary telescope. This is very difficult work, especially in thelowermost spectrum, where I have spent over two weeks of consecutivelabor in fixing a single wave-length.

The final result is, I think, worth, the trouble, however, for, as yousee here, we are now able to fix with approximate precision and bydirect experiment, the wave-length of every prismatic spectral ray. Theterminal ray of the solar spectrum, whose presence has been certainlyfelt by the bolometer, has a wave-length of about 28,000 (or is nearlytwo octaves below the "great A" of Fraunhofer).

So far, it appears only that we have been measuring _heat_, but Ihave called the curve that of solar "energy," because by a series ofindependent investigations, not here given, the selective absorptionof the silver, the speculum-metal, the glass, and the lamp-black(the latter used on the bolometer-strip), forming the agents ofinvestigation, has been separately allowed for. My study of lamp-blackabsorption, I should add in qualification, is not quite complete. I havefound it quite transparent to certain infra-red rays, and it is verypossible that there may be some faint radiations yet to be discoveredeven below those here indicated.

In view of the increased attention that is doubtless soon to be givento this most interesting but strangely neglected region, and which byphotography and other methods is certain to be fully mapped hereafter, Ican but consider this present work less as a survey than as a sketch ofthis great new field, and it is as such only that I here present it.

All that has preceded is subordinate to the main research, on which Ihave occupied the past two years at Alleghany, in comparing the spectraof the sun at high and low altitudes, but which I must here touch uponbriefly. By the generosity of a friend of the Alleghany Observatory, andby the aid of Gen. Hazen, Chief Signal Officer of the U S. Army, I wasenabled last year to organize an expedition to Mount Whitney in SouthCalifornia, where the most important of these latter observations wererepeated at an altitude of 13,000 feet. Upon my return I made a specialinvestigation upon the selective absorption of the sun's atmosphere,with results which I can now only allude to.

By such observations, but by methods too elaborate for presentdescription, we can pass from the curve of energy actually observed tothat which would be seen if the observer were stationed wholly above theearth's atmosphere, and freed from the effect of its absorption.

The salient and remarkable result is the growth of the blue end of thespectrum, and I would remark that, while it has been long known fromthe researches of Lockyer, Crova, and others that certain rays of shortwave-length were more absorbed than those of long, these charts show_how much_ separate each ray of the spectrum has grown, and bring, whatseems to me, conclusive evidence of the shifting of the point of maximumenergy without the atmosphere toward the blue. Contrary to the acceptedbelief, it appears here also that the absorption on the whole grows lessand less, to the extreme infra-red extremity; and on the other hand,that the energy before absorption was so enormously greater in the blueand violet, that the sun must have a decidedly bluish tint to the nakedeye, if we could rise above the earth's atmosphere to view it.

But even were we placed outside the earth's atmosphere, that surroundingthe sun itself would still remain, and exert absorption. By specialmethods, not here detailed, we have at Alleghany compared theabsorption, at various depths, of the sun's own atmosphere for eachspectral ray, and are hence enabled to show, with approximate truth, Ithink for the first time, the original distribution of energy throughoutthe visible and invisible spectrum at the fount of that energy, in thesun itself. There is a surprising similarity, you will notice, in thecharacter of the solar and telluric absorptions, and one which we couldhardly have anticipated _a priori_.

Here, too, violet has been absorbed enormously more than the green, andthe green than the red, and so on, the difference being so great, thatif we were to calculate the thickness of the solar atmosphere on thehypothesis of a uniform transmission, we should obtain a very thickatmosphere from the rate of absorption in the infra-red alone, and avery thin one from that in the violet alone.

But the main result seems to be still this, that as we have seen in theearth's atmosphere, so we see in the sun's, an enormous and progressiveincrease of the energy toward the shorter wave-lengths. This conclusion,which, I may be permitted to remark, I anticipated in a communicationpublished in the _Comptes Rendus_ of the Institute of France as longsince as 1875, is now fully confirmed, and I may mention that it is soalso by direct photometric methods, not here given.

If, then, we ask how the solar photosphere would appear to the eye,could we see it without absorption, these figures appear to showconclusively that it would be _blue_. Not to rely on any assumption,however, we have, by various methods at Allegheny, reproduced thiscolor.

Thus (to indicate roughly the principle used), taking three Maxwell'sdisks, a red, green, and blue, so as to reproduce white, we note thethree corresponding ordinates at the earth's surface spectrum, and,comparing these with the same ordinates in the curve giving the energyat the solar surface, we rearrange the disks, so as to give theproportion of red, green, and blue which would be seen _there_, andobtain by their revolution a tint which must approximately representthat at the photosphere, and which is most similar to that of a bluenear Fraunhofer's "F."

The conclusion, then, is that, while all radiations emanate from thesolar surface, including red and infra-red, in greater degree than wereceive them, the blue end is so enormously greater in proportion thatthe proper color of the sun, as seen at the photosphere is blue--notonly "bluish," but positively and distinctly blue; a statement which Ihave not ventured to make from any conjecture, or on any less cause thanon the sole ground of long continued experiments, which, commenced someseven years since, have within the past two years irresistibly tended tothe present conclusion.

The mass of observations on which it rests must be reserved for moredetailed publication elsewhere. At present, I can only thank theassociation for the courtesy which has given me the much prizedopportunity of laying before them this indication of methods andresults.

* * * * *

THE MINERALOGICAL LOCALITIES IN AND AROUND NEW YORK CITY, AND THEMINERALS OCCURRING THEREIN.

[Footnote: Continued from SUPPLEMENTS 244 and 246.]

By NELSON H. DABTON.

PART III.

Hoboken.--The locality represented here is where the same serpentinethat we met on Staten Island crops out, and is known as Castle Hill. Itis a prominent object in view when on the Hudson River, lying on CastlePoint just above the Stevens Institute and about a mile north of theferry from Barclay or Christopher Street, New York city. Upon it is theStevens estate, etc., which is ordinarily inaccessible, but below thisand along the river walk, commencing at Fifth Street and to Twelfth,there is an almost uninterrupted outcrop from two to thirty feet inthickness and plentifully interspersed with the veins of the mineralsof the locality, which are very similar to those of Staten Island; theserpentine, however, presenting quite a different appearance, being of adenser and more homogeneous structure and color, and not so brittle orlight colored as that of Staten Island, but of a pure green color. Theveins of minerals are about a half an inch to--in the case of drusesof magnesite, which penetrate the rock in all proportions anddirections--even six inches in thickness. They lie generally in aperpendicular position, but are frequently bent and contorted in everydirection. They are the more abundant where the rock is soft, as veins,but included minerals are more plentiful in the harder rock. There ishardly any one point on the outcrop that may be said to be favored inabundance, but the veins of the brucites, dolomite, and magnesites arescattered at regular and short intervals, except perhaps the last, whichis most plentiful at the north end of the walk.

_Magnesite_.--This mineral, of which we obtained some fine specimens onStaten Island, occurs extremely plentifully here, constituting five orsix per cent. of a large proportion of the rock, and in every imaginablecondition, from a smooth, even, dark colored mass apparently devoid ofcrystalline form, to druses of very small but beautiful crystals, whichare obtained by selecting a vein with an opening say from a quarter to ahalf-inch between it and one or, if possible, both points of its contactwith the inclosing rock, and cutting away the massive magnesite and rockaround it, when fine druses and masses or geodes may be generally foundand carefully cut out. The crystals are generally less than a quarter ofan inch long, and the selection of a cabinet specimen should be basedmore upon their form of aggregation that the size of the crystals.Nearly all the veins hold more or less of these masses through theirtotal extent, but many have been removed, and consequently a carefulsearch over the veins for the above indications, of which there arestill plenty undeveloped or but partly so, would well repay an houror more of cutting into, by the specimens obtained. Patience is anexcellent and very necessary virtue in searching for pockets ofminerals, and is even more necessary here among the multitudinous barrenveins. One hint I might add, which is of final importance, and theignorance of which has so far preserved this old locality fromexhaustion, is that every specimen of this kind in the serpentine, ofany great uniqueness, is to be found within five feet from the upper orsurface end of the vein, which in this locality is inaccessible in themore favored parts without a ladder or similar arrangement upon whichone may work to reach them. Here the veins will be found to be very fardisintegrated and cavernous, thus possessing the requisite conditions ofoccurrence (this is also true of Staten Island, but there more or lessinaccessible) for this mineral and similar ones that occur in geodes ordrused incrustations, while it is just _vice versa_ for those occurringin closely packed veins, as brucite, soapstone, asbestos, etc., wherethey occur in finer specimens, where they are the more compact, which isdeep underground. This is also partly true of the zeolites and granularlimestone species with included minerals. I do not think there is anyrule, at least I have not observed it in an extended mineralogicalexperience; but if they favor any part, it is undoubtedly the top, asin the granular limestone and granite; however, they generally fallsubordinate to the first principle, as they more frequently, in thisformation, with the exception of chromic iron, occur not in theserpentine but in the veins therein contained; for instance, crystalsof dolomite are found deeper in the rock as they occur in the densersoapstone, which becomes so at a more or less considerable depth, withspinel, zircon, etc., of the granular limestone. They occur generally inpockets within five feat from the surface, but they can hardly be calledincluded minerals, as they are rather, as their mention suggests,pockets, and adjacent or in contact with the intruded granite ormetamorphosed rock joining the formation at this point. This isseemingly at variance when we consider datholite, but when we do find itin pockets a hundred and fifty feet below the surface, in the Weehawkentunnel, it is not in the trap, but on the surface of what was a cleftor empty vein, since filled up with chlorite extending from the surfacedown, while natrolite, etc., by the trap having clefts of such variableand often great depth, allowed the solution of the portion thuscontributed that infiltered from the surface easy access to the bedsin which they lie, the mode of access being since filled with denselypacked calcite, which was present in over-abundance. This is notapplicable to serpentine, as the clefts are never of any great depth,and the five feet before mentioned are a proportionately great depthfrom the surface. As I mentioned in commencing this paper (Part I),every part of the success of a trip lies in knowing where to find theminerals sought; and by close observation of these relations much moredirection may be obtained than by my trying to describe the exact pointin a locality where I have obtained them or seen them. There is muchmore satisfaction in finding rich pockets independently of direction,and by close observance of indications rather than chance, or by havingthem pointed out; for the one that reads this, and goes ahead of you tothe spot, and either destroys the remainder by promiscuous cuttings, orcarries them off in bulk, as there are many who go to a locality, andwhat they cannot carry off they destroy, give you a disappointment infinding nothing; consequently, I have considered that this digressionfrom our subject in detail was pardonable, that one may be independentof the stated parts of the locality, and not too confidently rely onthem, as I am sometimes disappointed myself in localities and pocketsthat I discover in spare time by finding that some one has been therebetween times, and carried off the remainder. The characteristics ofmagnesite I have detailed under that head under Pavilion Hill, StatenIsland; but it may be well to repeat them briefly here. Form as abovedescribed, from a white to darker dirty color. Specific gravity, 2.8-3;hardness, about 3.5. Before the blowpipe it is infusible, _and notreduced to quicklime_, which distinguishes it from dolomite, which itfrequently resembles in the latter's massive form, common here in veins.It dissolves in acid readily with but little effervescence, whichlittle, however, distinguishes it from brucite, which it sometimesresembles and which has a much lower-specific gravity when pure.

_Dolomite_.--This mineral has been very common in this locality.It differs, perhaps, as I have before explained, from magnesite incontaining lime besides magnesia, and from calc spar by the _viceversa_. Much of the magnesite in this serpentine contains more or lesslime, and is consequently in places almost pure dolomite, althoughcrystals are seldom to be found in this outcrop, it all occurring asveins about a half-inch thick and resembling somewhat the gurhofiteof Staten Island, only that it is softer and less homogeneous inappearance. Its color is slightly tinged green, and specimens of it arenot peculiarly unique, but perhaps worth removing. Its characteristicsare: first, its burning to quicklime before the blowpipe, distinguishingit from pure magnesite; second, its slow effervescence in acids. Besidesthese, its specific gravity is 2.8, hardness, 8.5; from calcspar itcannot be distinguished except by chemical analysis, as the two speciesblend almost completely with every intermediate stage of compositioninto either calc spar, or, what occurs in this locality, aragonite,similar in composition to it, or dolomite. The color of the last,however, is generally darker, and it cleaves less readily into itscrystalline form, which is similar to calc spar, and of which it isharder, 3.5 to 3 of calc spar.

_Aragonite_.--This mineral, identical in composition with calc spar, butwhose crystalline form is entirely different, occurs in this locality inveins hardly recognizable from the magnesite or dolomite, and runninginto dolomite. It is not abundant, and the veins are limited in extent;the only distinguishment it has from the dolomite, practically, is itsfibrous structure, the fibers being brittle and very coarse. If examinedwith a powerful glass, they will be seen to be made up of modified longprisms. The specific gravity is over 2.9, hardness about 4, unless muchweathered, when it becomes apparently less. There are some small veinsat the north end of the walk, and in them excellent forms may be foundby cutting into the veins.

_Brucite_.--This mineral occurs here in fair abundance, it being one ofthe principal localities for it in the United States, and where formerlyextremely unique specimens were to be obtained. It has been pretty wellexhausted, however, and the fine specimens are only to be obtained bydigging into the veins of it in the rock, which are quite abundant onthe south end of the walk, and, as I before noted, as deep as possiblefrom the top of the veins, as it is a closely packed mineral notoccurring in geodes, druses, etc. Two forms of it occur; the one,nemalite, is in fibers of a white to brown color resembling asbestos,but the fibers are brittle, and hardly as fine as a typical asbestos. Itis packed in masses resembling the brucite, from which it only differsin breaking into fibers instead of plates, as I have explained in mydescription of that species (see Part II). They are both readily solublein acids, with effervescence, and infusible but crumble to powder beforethe blowpipe, or at least become brittle; when rubbed in mass with apiece of iron, they phosphoresce with a yellow light; specific gravity,2.4, hardness, 1.5 to 2. Its ready solubility in acids withouteffervescence at once distinguishes it from any mineral that it mayresemble. The specimens of nemalite may be more readily obtained thanthe brucite but fine specimens of both may be obtained after finding avein of it, by cutting away the rock, which is not hard to do, as itis in layers and masses packed together, and which maybe wedged out inlarge masses at a time with the cold chisel and hammer, perhaps at therate of three or four cubic feet an hour for the first hour, and inrapidly decreasing rate as progress is made toward the unweathered rockand untouched brucite, etc.

_Serpentine_.--Fair specimens of this may be obtained of a dark oilgreen color, but not translucent or peculiarly perfect forms. Thevariety known as marmolite, which splits into thin leaves, is plentifuland often well worth removing.

_Chromic Iron_.--Crystals of this are included in the denser rockin great abundance; they are very small, seldom over a few linesin diameter, of an iron black color, of a regular octahedral form;sometimes large crystals may be found in place or in the disintegratedloose rock. I have seen them a half inch in diameter, and a half dozenin a small mass, thus forming an excellent cabinet specimen. By findingout by observation where they are the thickest in the rock, and cuttingin at this point, more or less fine crystals may be obtained. This isreadily found where they are so very abundant, near the equidistantpoints of the walk, that no difficulty should be encountered in sodoing. These characteristics are interesting, and if large specimenscannot be obtained, any quantity of the small crystals may be split out,and, as a group, used for a representative at least. Before the blowpipeit is infusible, but if powdered, it slowly dissolves in the moltenborax bead and yields a beautiful green globule. The specific gravity,which is generally unattainable, is about 4.5, and hardness 5 to 6. Itspowder or small fragments are attracted by the magnet. A few small veinsof this mineral are also to be found horizontally in the rock, andsmall masses may be obtained. They are very rare, however. I have seennumerous agates from this locality, but have not found them theremyself. They may be looked for in the loose earth over the outcrop, oralong the wall of the river. Our next locality is Paterson, N. J., orrather in a trip first to West Paterson by the D.L. & W. Railroad,Boonton branch, then back to Paterson proper, which is but a shortdistance, and then home by the Erie road, or, if an excursion ticket hasbeen bought, on the D.L. & W, back from West Paterson. Garret Rock holdsthe minerals of Paterson, and although they are few in number, are veryunique. The first is phrenite. This beautiful mineral occurs ingeodes, or veins of them, near the surface of the basalt, which is thecharacteristic formation here, and lies on the red sandstone.

These veins are but two or three feet from the surface, and the onesfrom which the fine specimens are to be and have been obtained areexposed by the railroad cutting about a thousand feet north of thestation at West Paterson, and on the west side of the rails. Near orbelow the beds is a small pile of debris, prominent by being the onlyone in the vicinity near the rails. In this loose rock and the veinswhich are by this description readily found and identified, they areabout three inches in thickness, and in some places widen out intopockets even a foot in diameter They look like seams of a dark earth,with blotches of white or green matter where they are weathered, but arefresher in appearance inside. The rock, in the immediate vicinity of theveins, is soft, and may be readily broken out with the hammer of, ifpossible, a pick bar, and thus some of these geode cavities broken into,and much finer specimens obtained than in the vein proper. Considerableoccurs scattered about in the before-mentioned pile of loose rock anddebris, and if one does not prize it sufficiently to cut into the rock,taking the chances of lucky find, plenty may be obtained thus; but asit has been pretty thoroughly picked over where loose, it is much moresatisfactory to obtain the fine specimens in place in the rock. Whenthe bed for the railroad was being cut here, many fine specimens wereobtained by those in the vicinity, and the natives of the place have itin abundance, and it may be obtained from many of them for a trifle, ifone is not inclined to work it out. The mineral itself occurs in massesin the vein of a white, greenish white, or more or less dark greencolor. Sometimes yellowish crystals of it occur plentifully in shortthick prisms, but the common form is that of round coralloid bunches,having a radiated structure within. Sometimes it is in masses made upof a structure resembling the leaves of a book slightly opened, and innearly every shape and size. Crystals of the various forms may be wellsecured, and also the different colors from the deep green to the bluewhite, always remembering that true, perfect crystals are of more valuethan masses or attempted forms. The specific gravity is 2.8 to2.9, hardness nearly 7 before the blowpipe; it readily fuses afterintumescing; it dissolves in hot acid without gelatinizing, leaving aflaky residue.

_Datholite_.--This mineral is very abundant as inferior specimens, andfrequently very fine ones may be obtained. They occur all around GarretRock at the juncture of the basalt and red sandstone, in pockets, and asheavy druses. They are most abundant near the rock cuttings between WestPaterson and Paterson, and may be cut out by patient labor. This is along known and somewhat noted locality for datholite, and no difficultyneed be experienced in obtaining plenty of fair specimens. Near them isthe red sandstone, lying under the basalt, and baked to a scoriaceouscinder. Upon this is a layer of datholite in the form of a crystallineplate, and over or above this, either in the basalt or hanging down intocavities in the sandstone, are the crystals or geodes of datholite. Oldspots are generally exhausted, and consequently every new comer has tohunt up new pockets, but as this is readily done, I will not expendfurther comment on the matter. The datholite, as in other localities,consists of groups of small colorless crystals. Hardness, about 5;specific gravity, 3. Before the blowpipe it intumesces and melts to aglassy globule coloring the flame green, and forms a jelly when boiledwith the acids.

_Pectolite_--This mineral is also quite abundant in places, the greaterpart occurring with or near the phrenite before mentioned, in smallmasses generally more or less weathered, but in very fair specimens,which are about an inch in thickness. It is readily recognized by itspeculiar appearance, which, I may again repeat, is in fibrous masses,these fibers being set together in radiated forms, and are quite toughand flexible, of a white color, and readily fused to a globule beforethe blowpipe.

_Feldspar_.--This mineral occurs strewn over the hill from place toplace, and is peculiarly characterized by its lively flesh red color,quite different from the dull yellowish gray of that from Staten Islandor Bergen Hill. Fine crystals of it are rather rare, but beautifulspecimens of broken groups may be obtained in loose debris around thehill and in its center. I have not been able to locate the vein or veinsfrom which it has come, but persistent search will probably reveal it,or it may be stumbled upon by accident. Some of the residents of thevicinity have some fine specimens, and it is possible that they candirect to a plentiful locality. However, some specimens are well wortha thorough search, and possess considerable value as mineralogiealspecimens. The specific gravity of the mineral is 2.6, and it has ahardness of 6 before the blowpipe. It is with difficulty fused to aglobule, more or less transparent. It occurs undoubtedly in veins in thebasalt and near the surface of the outcrop As this locality has neverbefore been mentioned as affording this species, it is fresh to theamateur and other mineralogists, and there need be no difficulty inobtaining some fine specimens. Its brilliant color distinguishes it fromother minerals of the locality.

It is possible that some of the other zeolites as mentioned under BergenHill occur here, but I have not been able to find them. The reasonmay be that the rock is but little cut into, and consequently no newunaltered veins are exposed.

COPPER MINES, ARLINGTON, N. J.--A short distance north of this station,on the New York and Greenwood Lake Railroad, and about nine miles fromJersey City, is one of the cuttings into the deposits of copper whichpermeate many portions of the red sandstone of this and the allieddistricts in Connecticut and Massachusetts, and which have been soextensively worked further south at Somerville and New Brunswick, etc.There are quite a variety of copper minerals occurring in these mines,and as they differ but little in anything but abundance, I will describethis, the one nearest to New York City, as I promised in commencingthese papers. The locality of this mine may be readily found, as it isnear the old turnpike from Jersey City, along which the water-pipes oraqueduct, are laid. By taking the road directly opposite to the stationat Arlington, walking north to its end, which is a short distance, thenturning to the left along the road, there crossing and turning north upthe next road joining this, until the turnpike is reached; this is thenfollowed east for about a quarter-mile, passing occasional heaps in theroad of green earth, until the head of a descent is reached, when weturn off into the field to the left, and there find the mine near theheaps of greenish rocks and ore scattered about, a distance from thestation of about a mile and a half through a pleasing country. Theentrance to the mine is to the right of the bank of white earth on theedge of, and in the east side of the hill; it is a tunnel more or lesscaved in, running in under the heaps of rock for some distance. It willnot be necessary, even if it were safe, to venture into the mine, butall the specimens mentioned below may be obtained from the heaps of oreand rock outside, and in the outcrops in the east side of the hill, alittle north of the mouth of the tunnel to the mine. The hammer and coldchisel will be necessary, and about three hours should be allowed tostay, taking the noon train from New York there, and the 5.09 P.M. trainin return, or the 6.30 A.M. train from the city, and the 1.57 P.M. inreturn. This will give ample opportunity for the selection of specimens,and, if time is left, to visit the water works, etc.

_Green Malachite_.--This is the prominent mineral of the locality, andis conspicuous by its rich green color on all the rocks and in theoutcrops. Fine specimens of it form excellent cabinet specimens. Itshould be in masses of good size, with a silky, divergent, fibrousstructure, quite hard, and of a pure oil green color, for this purpose.Drused crystals of it are also very beautiful and abundant, but veryminute. As the greater part of it is but a sixteenth or eighth of aninch in thickness, it may require some searching to secure large massesa quarter to a half-inch in thickness, but there was considerable, bothin the rock, debris, and outcrop, remaining the last visit I made to theplace a few months ago. The mineral is so characterized by its color andsolubility in acid that a detailed description of it is unnecessary toserve to distinguish it. Its specific gravity is 4, and hardness about4. It decrepitates before the blowpipe, but when fused with some boraxin a small hollow on a piece of wood charcoal, gives a globule ofcopper. It readily dissolves in acids, with effervescence, as it is acarbonate of copper.

_Red Oxide of Copper_--This rather rare mineral is found in smallquantities in this mine, or near it, in the debris or outcrop. Perfectcrystals, which are of a dodecahedral or octahedral form, are fairlyabundant. They are difficult to distinguish, as they are generallycoated, or soiled at least, with malachite. The color proper is ofa brownish red, and the hardness about 4, although sometimes, it isearthy, with an apparent hardness not over 2. The crystals are generallyabout a quarter of an inch to a half of an inch in diameter, and foundinside the masses of malachite. When these are broken open, the redcopper oxide is readily distinguished, and may be separated or broughtinto relief by carefully trimming away the malachite surrounding it asits gravity (6) is much greater than malachite. When a piece of the lastis found which has a high gravity, it may be suspected and broken into,as this species is much more valuable and rarer than the malachitewhich is so abundant. It dissolves in acids like malachite, but withouteffervescence, if it be freed from that mineral, and acts the samebefore the blowpipe. Sometimes it may be found as an earthy substance,but is difficult to distinguish from the red sandstone accompanyit,which both varieties resemble, but which, not being soluble in theacids, find having the blowpipe reactions, is thus characterized. Thisred oxide of copper does not form a particularly showy cabinet specimen,but its rarity and value fully compensate for a search after it. I havefound considerable of it here, and seen some little of it in placeremaining.

_Chrysorolla_.--This mineral, very abundant in this locality, resemblesmalachite, but has a much bluer, lighter color, without the fibrousstructure so often present in malachite, and seldom in masses, it onlyoccurring as light druses and incrustations, some of which are verybeautiful, and make very fine cabinet specimens. Its hardness is lessthan that of the other species, being under 3, and a specific gravityof only 2, but as it frequently occurs mixed with them, is difficult todistinguish. It does not dissolve in nitric acid, although that takesthe characteristic green color of a solution of nitrate of copper,as from malachite or red oxide. This species is found all over thislocality, and a fine drused mass of it will form an excellent memento ofthe trip.

_Copper Glance_.--This mineral is quite abundant in places here, butfine crystals, even small, as it all is, are rare. That which I haveseen has been embedded in the loose rock above the mine, about a quarterinch in diameter, and more or less disguised by a green coating ofchrysocolla. The color of the mineral itself is a glistening grayishlead color, resembling chromite somewhat in appearance, but the crystalsof an entirely different shape, being highly modified or indistinctrhombic prisms. The specific gravity is over 5, and the hardness 4.Before the blowpipe on a piece of wood charcoal it gives off fumes ofsulphur, fuses, boils, and finally leaves a globule of copper. In nitricacid it dissolves, but the sulphur in combination with it separates asa white powder. A steel knife blade placed in this solution receives acoating of copper known by its red color.

_Erubescite_--This mineral occurs massive in the rock here with theother copper minerals, and is of a yellowish red color, more or lesstarnished to a light brown on its surface, Before the blowpipe oncharcoal it fuses, burns, and affords a globule of copper and iron,which is attracted by the magnet. Its specific gravity is 5, hardness3. It resembles somewhat the red oxide, but the low gravity, inferiorhardness, lighter color, and blowpipe reaction distinguish it. Theseare the only copper minerals likely to be found at this mine, and thefollowing table and note will show their characteristics:

Malachite is characterized by its color from Copper Glance and Red Oxideand Erubescite, and from Chrysocolla by the action of the acid, thefibrous structure and blowpipe reaction, gravity, and hardness.

Red Oxide is distinguished from Erubescite, which it alone resembles,by its darker color, higher specific gravity, and yielding a globule ofpure copper.

Chrysocolla is characterized by its low specific gravity, light color,lack of fibrous structure, blowpipe reactions, and the acid.

Copper Glance is distinguished by its color, fumes of sulphur, andglobule of copper.

Erubescite is distinguished from Red Oxide, which it alone resembles, byits lighter color, great solubility when pure, and yielding a magneticglobule before the blowpipe in the hollow of a piece of wood charcoal,which is used instead of platinum wire in this investigation.

* * * * *

ENTOMOLOGY.

[Footnote: From the _American Naturalist_, November, 1882.]

THE BUCKEYE LEAF STEM BORER.--In our account of the proceedings of theentomological sub-section of the A.A.A.S., at the 1881 meeting (see_American Naturalist_, 1881, p. 1009), we gave a short abstract of Mr.E.W. Claypole's paper on the above insect, accepting the determinationof the species as _Sericoris instrutana_, and mentioning the fact thatthe work of _Proteoteras aesculana_ Riley upon maple and buckeye was verysimilar. A letter recently received from Mr. Claypole, prior to sendinghis article to press, and some specimens which be had kindly submittedto us, permit of some corrections and definite statements. We have asingle specimen in our collection, bred from a larva found feeding, in1873, on the blossoms of buckeye, and identical with Mr. Claypole'sspecimens, which are in too poor condition for description or positivedetermination. With this material and with Mr Claypole's observationsand our own notes, the following facts are established:

1st. We have _Proteoteras aesculana_ boring in the terminal green twigsof both maple and buckeye, in Missouri, and often producing a swellingor pseudo-gall. Exceptionally it works in the leaf-stalk. It also feedson the samara of maple, as we reared the moth in June, 1881, fromlarvae infesting these winged seeds that had been collected by Mr. A.J.Wethersby, of Cincinnati, O.

2d. We have an allied species, boring in the leaf-stalk of buckeye,in Ohio, as observed by Mr. Claypole. It bears some resemblanceto _Proteoteras aesculana_, but differs from it in the followingparticulars, so far as can be ascertained from the poor materialexamined: The primaries are shorter and more acuminate at apex.Their general color is paler, with the dark markings less distinctlyseparated. No distinct tufts of scales or knobs appear, and theocellated region is traversed by four or five dark longitudinal lines.It would be difficult to distinguish it from a rubbed and faded specimenof _aesculana_, were it not for the form of the wing, on which, however,one dare not count too confidently. It probably belongs to the samegenus, and we would propose for it the name of _claypoleana_. Thelarva is distinguished from that of _aesculana_ by having the minutegranulations of the skin smooth, whereas in the latter each granule hasa minute sharp point.

3d. _Sericoris instrutana_ is a totally different insect. Hence ourprevious remarks as to the diversity of food-habit in this species haveno force--_C.V.R._

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DEFOLIATION OF OAK TREES BY DRYOCAMPA SENATORIA IN PERRY COUNTY,PA.--During the present autumn the woods and road-sides in thisneighborhood (New Bloomfield) present a singular appearance inconsequence of the ravages of the black and yellow larva of the abovespecies. It is more abundant, so I am informed, than it has ever beenbefore. In some places hardly any trees of the two species to which itsattack is here limited have escaped. These are the black or yellow oak(_Q. tinctoria_) with its variety (_coccinea_), the scarlet oak and, thescrub oak (_Q. ilicifolia_). These trees appear brown on the hill-sidesfrom a distance, in consequence of being altogether stripped oftheir leaves. The sound of the falling frass from the thousands ofcaterpillars resembles a shower of rain. They crawl in thousands overthe ground, ten or twelve being sometimes seen on a square yard. Thesprings and pools are crowded with drowned specimens. They are equallyabundant in all parts of the county which I have visited during thepast week or two--the central and southeastern.--_E. W. Olaypole, NewBloomfield, Pa_.

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EFFICACY OF CHALCID EGG-PARASITES.--Egg-parasites are among the mostefficient destroyers of insects injurious to vegetation, since they killtheir victim before it has begun to do any damage; but few persons areaware of the vast numbers in which these tiny parasites occasionallyappear. Owing to the abundance of one of them (_Trichogramma pretiosa_Riley), we have known the last brood of the cotton-worm to beannihilated, and Mr. H.G. Hubbard reported the same experience atCenterville, Fla. Miss Mary E. Murtfeldt has recently communicated to usa similar experience with a species of the Proctotrupid genus Telenomus,infesting the eggs of the notorious squash-bug (_Coreus tristis_). Shewrites: "The eggs of the Coreus have been very abundant on our squashand melon vines, but fully ninety per cent. of them thus far [August 2]have been parasitized--the only thing that has saved the plants fromutter destruction."